well i dont know the Hamilton area that well.. I do know there is a Big Al's up there..
In Mississauga we have a Big Als too.. we also have a couple in some Asian strip malls. There is Dragon Aquarium (dundas and tomken), and AquaPets at Burnhamthorpe and Creditview..
Brampton also has a Big Al's..and i'm sure they have other stores, but you'd prolly have to do some hunting around..
Petsmart also has a pretty okay selection, but i find their staff isnt that knowledgeable..
hope this helps!